1. Field of the Invention
The present invention generally relates to a metal bump structure and a method for forming the same. In particular, the present invention is directed to a metal bump structure for use in a driver IC to be protected from an ambient atmosphere, free of a galvanic effect in the presence of high electric field or halogen as well as a method for forming the same.
2. Description of the Prior Art
In some electronic circuits, metal bumps are used to form connections between two groups of circuits. In order to lower the inevitable contact resistance and to achieve the best possible results, copper is often used as the first choice of the metal bump material.
Generally speaking, copper is an ideal metal to serve as a metal bump material because it is not chemically active and has extremely low electric resistance. However, in some application cases, copper which serves as a metal bump material suffers serious damages due to an undesirable phenomenon, namely galvanic effect, in the presence of extreme or abnormal conditions. This is adverse to the electronic circuits.
Further, metal bumps made of other metals, such as gold, are extremely difficult to re-work once the metal bumps are flawed because aqua regia for re-working is a very corrosive chemical agent. When the electronic circuits with the flawed metal bumps are re-worked anyway, the reliability of the electronic circuits is possibly seriously compromised.